Vehicle speed measurement and enforcement systems can be employed to monitor traffic and identify vehicles moving faster than the posted speed limit. Such vehicle speed measurement systems can employ remote sensing devices such as those based on, for example, Radar (Radio Detection and Ranging) or LIDAR (Light Detection and Ranging) to determine the accurate speed of a vehicle by directing a narrow beam of radiation at a vehicle target and analyzing reflected radiation. RADAR or “radar” devices generally utilize radio waves and operate based on the Doppler principle, wherein the frequency of the reflected radiation is shifted according to the relative velocity of the target. LIDAR or “lidar” devices, on the other hand, utilize a laser beam, typically at infra-red frequency, and compute the relative velocity from a time-of-flight calculation performed on the reflected radiation.
The majority of prior art vehicle speed measurement systems utilize a hand-held and/or a vehicle-mounted device to detect the speed of the moving vehicle. Such devices must be aimed directly at the target vehicle and measure only the component of the vehicle velocity directly in a straight line between the device and the vehicle. Consequently, such devices suffer from “cosine error” in real-life situations such as on curved roads, hilly terrain, location of the device on the side of the road or an overhead gantry, etc. Additionally, such hand-held and vehicle-mounted devices must be manually operated by a certified officer and possess an inability to operate in an automated and unattended mode which render them unsuitable for managed transportation services.
Based on the foregoing, it is believed that a need exists for an improved automated vehicle speed measurement and enforcement system and method in order to perform the unattended operation and to correct a cosine error, as described in greater detail herein.